Tenant's title to the property

Please tell me the legal position regarding this situation. A man named O was allotted a flat in Delhi by a Company. This man sub lets the flat to a tenant. He collects the rent for 7 months. After seven months, he disappears into thin air. The tenant keeps on residing in that flat. After the span of 30 years, some property dealers start making calls to this tenant saying that he i.e. the tenant has encroached upon the property of the original allotee and offers are thrown upon the tenant to take some amount and vacate the property. Panicked, the tenant takes advice from an Advocate who advises him to mutate the electricity and water bills in his name. The son of the tenant makes a forged General power of Attorney and gets mutated the electricity bill in the name of his father. Now, somebody named and styled as the original allottee files complaint in the Electricity Company’s office that the GPA signed is forged. Consequently, the Electricity company issues notice to the tenant to prove his title to the property else his electricity connection will be cut. Now please provide with the remedy available to the tenant in view of the point that the tenant and his family have been in the peaceful adverse possession of the flat for last 30 years.